Oven for burning refractories and the like



June 26, 1928.

H. KOPPERS OVEN FOR BURNING REFRACTORIES AND THE LIKE Original Filed Aug. 31. 1921 Sheets-Sheet l 3' [III llll

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Patented June 26, 1928.

UNITED STATES OPMENT CORPORATION, PENNSYLVANIA.

PATENT OFFICE.

' HEINRICH 'K OPPEBS, OF ESSEN-RUHR, GERMANY, ASSIGNOR TO THE KOPPERS DEVEL- 01E PITTSBURGH, PENNSYLVANIA, A CORPORATION OF OVEN FOR BURNING REFRACTORIES AND THE LIKE.

Application filed August 31, 1921, Serial No. 497,364, and in Germany March 8, 1918. Renewed September 21, 1927.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1fi21, 41 STAT. I, 1818.)

The invention relates to a furnace plant for burning fireproof ware more particularly lime bonded, blocks of silica or dinas.

In burning lime bonded fireproof blocks 5 such as silica or dinas blocks, intermittently operated furnaces have heretofore been used,

- which are usually of round form and are charged by hand with the molded blocks; when the furnace chamber is full the contents are warmed up and attain after about nine to twelve days a maximum temperature of 1650 centigrade measured at the fire bridge, whereafter heating is continued for two to three days more at the high tempera- 5 him. The furnace is then quite closed, left the period of about three to four days. As

this alters the specific gravity from 2.65 to 2.3. a great expansion accompanies the burning. amounting to over 3% in the linear dimensions. If the blocks are not thus burnt, then later when the blocks are in use under high heat an expansion occurs which may be highly injurious to the furnace masonry under some conditions, especially in large furnaces, for example chamber ovens for the production of gas and coke, which nowadays have a length of tento twelve metres.

This manufactureof lime bonded blocks is however costly asv it requires much hand work. takes a long time, and consumes large quantities of coal; since the firing starts with the furnace cold, gas 'firing cannot well be employed. It has been attempted to simplify and cheapen the burning of such lime bonded blocks by using the ordinary channel furnace. In such a channel furnace as used in practice. of about 130 metres in length, the period between charging and discharging is only forty hours, so that the blocks are only a few hours in the actual burning zone, where they ought to remain for days. The con- -ous operation.

time the possibility is afforded to form the actual burning chamber in a way suitable for the economical and uniform development of the high temperature used therein. To this end the burning chamber is taken out of the plant which is otherwise formed as a channel furnace and forms a separately operated furnace, the number of the furnace chambers available thus permitting continu- By using suitable track arrangements the required circulation between the preheating chamber, burning chamber, and cooling chambers is made possible. It also becomes possible to construct the burning chamber itself in a way corresponding to the high development of furnace technics since it is now a separate and'independent entity. As the preheating of thefresh molded blocks is effected by the highly preheated air obtained from the cooling of the fully burnt blocks in the cooling chambers, it becomes possible to utilize the excess heat of the actual burning operation for this itself in a heat recovery plant, and thus to i'm prove the burning chamber in the Way of attaining a correspondingly higher temperature with a smaller consumption of heat. As the best basic form for this heat recovery plant, one with single chamber heaters or regenerators is recommended.

In the accompanying drawing a plant embodying the invention is illustrated in plan in Fig. 1 while Fig. 2 is a corresponding end view at line IIII of Fig. 1. Figs. 3 and 4 show in transverse and longitudinal section a construction of the actual burning chamber, Fig. 3 being on the line III of Fig. 4, and Fig. 4 being on line IV of Fig. 3

Near the preheating chamber 10 which is in the form of a channel furnace are located the similarly formed cooling chambers 11, two cooling chambers being assigned to one preheating chamber. because the cooling of the burnt lime bonded blocks must be very carefully done while the preheating of the molded blocks can proceed more rapidly. The cooling air introduced at the outlet end of the cooling chaml'iers by means of a blower flows over the hot ware stacked in the two chambers. which prehcats the said air, whereupon it leaves at the other end of the cooling chamber and enters the preheating channel 10 (see arrows in Fig. 1), through which it flows, in counter current to the freshly entered molded blocks, to the chimney or the suction blower. If necessary more gas can be supplied at the place of reversal through a pipe 15, to obtain by the additional combustion, an increase in the temperature of the discharge heat. The ware transported on the track 12 through the preheating channel 10 is delivered by means of a sliding platform 16 to the track 17 running at right angles thereto and which leads to the actual burning furnaces 18. four of which are provided here. The thus preheated ware is delivered to the burning furnaces and the blocks fully burnt therein, when by means of a sliding platform 20 running on the track 19 they are carried to the cooling chambers 11; to prevent cooling of the ware in this movement the sliding platform 12 is provided with. a hood 12' covered with fireproof material and if necessary heated. After the burnt blocks have cooled down in the chambers 11 the blocks are carried to the storage place by the sliding platform 14 on the track 13, and set down there.

In the illustrated plant, by using four burning furnaces. two cooling chambers. and one preheating chamber, there is obtained a burning time of four whole days, fortyone hours preheating time. and eighty-two hours cooling time: for the complete operation, thus a period of nine days and three hours: the relative dimensions of the dif ferent chambers giving a complete cyclic, uninterrupted operation.

The actual burning furnaces (see'Figs. 3 and 4) consist of chambers 21 arranged in pairs. above which the regenerators 23 and 24 and 23 and 24' are provided extending over their whole length. These regenerators operate together in the ,known way, viz, in one stage of working one regenerator serves as an air and gas heater and the other to store waste heat. while after about a half hours run a reversal of the draft is made and an exchange in functions occurs between the regenerators. Gas and air thus flow through the nozzle-like openings 25, 26 in the arch of the chamber 21 into the latter travcrsing it from top to bottom and are burnt, pass through the ducts 22 into the adJa-cent chamber, and flow through the openings 25', 26 into the regencrators :23, 24'. By the introduction of the flame down-wards'into the burning chamber a practically uniform flame impinging is attained, as here the hot gases more oppositely to the action of their buoyancy, so that they [ill the whole chamber owing to eddy formation and thus imby sand cups 338 so that the carriage frame can be cooled by an air passage 35 passing under the floor 32. and cut off from the burn ing chamber. and communicating with the atinos 'ihere or otherwise cooled.

The described kind of heating, by utilizing a high grade heat recovery plant, allows not only the development of the required high and uniform temperature in the burning chamber, butat the same time enables the pressure conditions to be accurately regulated in the. necessary manner. On the one hand no substantial amount of fresh air should be able to enter the burning chamber at the bottom, and on the other hand also no substantial amount of fire gases from the burning chamber should be able to descend through gaps between the chamber carriages. By arranging the regcnerators directly over the burning chamber the pressure conditions can be. so regulated that for example. at the level of the upper edge of the carriage frame a pressure condition of 0 prevails. Relatively to prior plants this yields an advantage since in chamber furnaces the fire gases move in counterflow to the ware and great friction has to be overcome in the long channels, so that it is never possible to maintain the required pressure conditions in the various parts of the burning furnace. The circumstance that the large excess heat' of the actual burning chamber is utilized in the associated heat recovery, yields the advantage that for the preheating of the freshly molded blocks only that heat is available, which is contained by the cooling air in the channels 11 from the burnt ware, so that the preheating does not become too rapid and therefore is not likely to cause cracking of the blocks.

The foundation 36.01 the burning and of the cooling chambers consists of concrete The sealing of all the burning chambers at the bottom is elfected till or like material and is separated from the fireproof material 37 by a layer of cast iron plates 27, which on the hot side are connected to water-cooled pipes 28 which are so disposed that they receivethe heat radiation between the chamber and the carriage wall and lead said heat away. 'lhcsc cast plates convey the heat, which would penctrate the foundation. to the water-cooled pipes and the latter thus carry away, all the otherwise injurious quantities of heat.

What is claimed is 1. A continuously operating plant for burning fireproof material, comprising a plurality of burning chambers, a prcheatmg chamber and a plurality of cooling chambers, said preheatingand cooling chambers being spaced from and operated independently of said burning chambers, and means for conveying material from said preheated chamber to said burning chambers and means for conveying the burnt: -material from the burning chambers to said cooling chambers.

2. A continuously operating plant for burning fireproof material. comprising a plurality of burning chan'ibers, a preheating chamber and a plurality of cooling chambers, said prehcatingand cooling chambers being spaced from and operated independently of said burning chambers, and means for conveying material from said preheat.- ed chamber to said burning chambers and means for conveying the burnt material from the burning chambers to said cooling chambers and covers for said material to prevent uncontrolled cooling of the mate rial while being conveyed.

A continuously operating plant for burning fireproof material comprising a pluralit-y of burning. chambers, a. preheating chamber and two cooling chambers serving said burning chambers, said preheating andcooling chambers being spaced from and operated independently of said burning chambers and means for conveying material from said preheating chamber to said burning chambers and means for conveying burntmaterial from said burning chambers to either of said cooling chambers, and means adapted to prevent uncontrolled cooling of said material while being conveyed between said chambers.

4. A continuously operating plant for burning fireproof material comprising a plurality of burning chambers, alternately acting regenerators therefor, one set of regenerators serving to preheat the fuels for combustion while the other serves to absorb the waste heat of the products of combustion, a preheating chamber and a plurality of cooling chambers, said preheating and cooling chambers being spaced from and operated independently of said burning chain bers and means for conveying material from said preheating chamber to said burning chambers and means for conveying burnt material from said burning chambers to said cooling chambers and means prcvcnt- 5. A continuously operating plant for burning fireproof material comprising a plurality of burning chambers disposed in pairs. alternately acting sets of rcgencrat'ors thcrcfor, one set operating to preheat air and gas for combustion while the other operates to absorb the'wasteheat of the products ol' such combustion, openings at the lower ends of said burning chambers through which the gases that {low from one sctol regenerators pass into the other burning chamber and llow up through the other set of regenerators to which the gases impart their waste heat. a preheating chamber and a plurality of cooling chambers, saidpreheating and cooling chambers being spaced from and operated independently of said burning chambers and means for conveying material between said burning chambers and said preheating and cooling chambers and means preventing uncontrolled cooling of said material while being conveyed between said chambers.

6. A continuously operating plant for burning fireproof material comprising a plurality of burning chambers disposed in pairs, alternately acting sets of regenerators therefor. one set operating to preheat fuels for combustion while the other operates to absorb the waste heat of such combustion, openings at the lower portions of said burning chambers through which the gases that flow down through one burning chamber pass to flow up through the other burning chamber and then to the other set of regenerators to impart waste heat thereto, means for carrying material to be burnt through said burning chambers, said means having a flooiuon which the material rests, a tunnel beneath said floor, said tunnel communicat ing with the atmosphere, a preheating chamher and a plurality of cooling chambers, said. preheating and cooling chambers being separated from and operated independently of said burning chain ers and means for conveying between said burning chambers and sald preheating and cooling chambers and means preventing uncontrolled cooling of the material while being conveyed.

7. A burning chamber for fireproof material comprising a foundation, fireproof blocks superimposed thereon formin side walls for said burning chamb ers, a division wall composed of fireproof material between said side walls, said wall together with a top and bottom and said side walls providing two burning chambers, metal plates interposed between said fireproof material and lIltl said foundation, and cooling pipes associated with the metal plates interposed between the division wall and the foundation.

8. A furnace plant for burning fireproof ware, more particularly lime bonded blocks (dinas, silica) characterized in that a plurality of sepa'ate burning chambers are separated from and operated independently of preheating and cooling chambers and to which the ware is supplied after preheating in preheating chambers operated in the manner of channel type furnaces, and from which it is conveyed. when completely burnt, to the cooling channels. a

9. A plant as described in claim 8. characterized in that two cooling channels are associated with each preheating channel in order to permit the cooling of the burnt ware to proceed gradually.

10. A burning chamber for fireproof plants comprising two burning channels separated by a division wall. openings in the lower portions of said division wall, said openings connnunicably connecting said burning channels with each other. regenerators individual to eachburning channel and connnunicably connected with the top thereof whereby when said channels are operating for burning the flow is from one regenerator down through one burning chanml and then through the openings in the division wall up through the other burning channel and through the regenerator.

11. A furnace plant for burning fireproof ware. having in combination a plurality of separate and contiguous intermittently operated burning chambers, a longitudinally extended preheating channel and longitudinally extended cooling channels at a distance from said burning chambers, said burning chambers being fired and operated independently of preheating and cooling chambers. means whereby the gases after their cooling operation are conducted from the cooling channels into the preheating 4 channel, means for transferring preheated material from the preheating channel to the burning chambers. means for transferring the burnt material from the furnace chambers to said cooling channel. and means ware, having in combination a plurality of a separate and contiguous intermittently operated burning chambers. a longitudinally extended preheating channel and longitudinally extended cooling channels, means whereby the gases after their cooling operation are conducted from the cooling chan nels into the preheating channel, each preheating channel being combined with a plurality of cooling channels. said burning chambers being spaced from and operated independently of said preheating and cooling chambers. means for transferring preheated material from the. preheating channel to the burning chambers. means for transferring the burnt material from the furnace chambers to said cooling channel. and means for gradually carrying the said materials through said channels oppositely to the flow of said gases therein.

13. A furnace plant. for burning fireproof ware. having in combination a plurality of separate and contiguous intermittently operated burning chambers having regenerators above them. means for supplying the combustion gases from said regenerators to the top of either burning chamber, and means for conducting the burnt gases from one furnace chamber to the other at the lower parts of said chambers.

In testimony whereof, I have hereunto set my hand this 25th day of July, 1921.

HEINRICH KOPPERS. 

